Pump system

ABSTRACT

A pump system including a pump and a valve for controlling flow of fluid from the pump to a controlled outlet in which the valve provides a controlled bypass of fluid from the pump during startup of the pump to delay opening of the controlled outlet until the pump has attained sufficient speed to sustain a predetermined pressure at the flow rates required for the controlled outlet, and in which the valve thereafter closes the bypass and controllably opens a relief passage to maintain the predetermined pressure at the controlled outlet. The valve is in the form of a self-contained unit detachably mounted on the pump housing to enable pretesting of the valve and ready replacement. A filter unit is mounted on the pump and surrounds the valve unit and the filter unit is arranged so that it can be removed and replaced without permitting filtered particles from reaching the pump or valve.

United States Patent [72] Inventor Kenneth E. Peterson 822 Hauthorne Ave., Rockford, 111. 61108 [21] Appl. No. 786,995 [22] Filed Dec. 26, 1968 {45] Patented Apr. 20, 1971 [54] PUMP SYSTEM 16 Claims, 6 Drawing Figs.

[52] U.S.Cl 210/416, 137/116,137/116,3 [51] 1nt.Cl B0ld 29/00, 801d 35/28 [50] Field ofSearch 210/416; 103/41,220, 39,40, 42; 137/1 16, 116.3

[56] References Cited UNITED STATES PATENTS 2,606,497 8/1952 Witherell 210/416X 2,654,323 10/1953 Wahlmark... 103/49 2,749,935 6/1956 Heard 131/116 2,880,674 4/1959 Klessig et'al. 103/220X Primary Examiner.lohn Adee Att0meyMc Carma, Morsbach, Pillote and Muir ABSTRACT: A pump system including a pump and a valve for controlling flow of fluid from the pump to a controlled outlet in which the valve provides a controlled bypass of fluid from the pump during startup of the pump to delay opening of the controlled outlet until the pump has attained sufficient speed to sustain a predetermined pressure at the flow rates required for the controlled outlet, and in which the valve thereafter closes the bypass and controllably opens a relief passage to maintain the predetermined pressure-at the controlled outlet. The valve is in the fom1 of a self-contained unit detachably mounted on the pump housing to enable pretesting of the valve and ready replacement. A filter unit is mounted on the pump and surrounds the valve unit and the filter unit is arranged so that it can be removed and replaced without permitting filtered particles from reaching the pump or valve.

stir/tr srrvr SUMMARY OF THE INVENTION Pumping systems for oil burners are intermittently operated as required to maintain the desired temperature conditions. llowever, the oil burner nozzles are generally such that they can properly atomize the fuel for complete combustion only when the liquid fuel is delivered to the nozzles in a predetermined pressure range. Problems are encountered in controlling flow of fuel to the nozzle for complete combustion of the fuel during startup and shutdown of the pumping system.

The pumping system includes a control valve having a pressure-operated valve member yieldably urged to a position blocking the flow to a controlled outlet. The valve includes a bypass passage for bypassing fluid from the pump during startup and until the pump has attained sufficient rotational speed to sustain a predetermined pressure at the controlled outlet. At that time, the valve member moves rapidly to a position opening the controlled outlet and closing ott bypass of fluid from the pump so that the full pump discharge is available for delivery to the controlled outlet. The pressureoperated valve member also controls flow through a relief passage to maintain the pressure on the fluid delivered to the controlled outlet in a selected range during normal pump operation. When the pump drive motor is deenergized, the valve member operates to regulate flow through the relief passage in a manner to maintain the predetermined pressure until the pump speed has slowed down to a point where the pump is no longer capable of maintaining the pressure at the flow rates required for the controlled outlet. The valve member then reopens the bypass passage to again bypass the fluid from the outlet of the pump so as to allow the valve member to rapidly move to a position closing the controlled outlet.

The valve is advantageously in the form of a separate removable unit detachably mounted on the pump so that the valve can be pretested and replaced as a unit. A filter is preferably provided and the filter is advantageously in the form of a separate removable unit detachably mounted on the pump housing to surround the valve so as to reduce the overall size of the pump valve and filter and provide convenient bypassing and recirculation of fluid. The filter unit has an inner compartmentwhich surrounds the valve and which stores a quantity of filtered fluid, and an outer filter compartment between the filter and the filter case, which outer filter compartment is enclosed except for the inlet opening to prevent filtered particles from reaching the pump or valve when the filter is removed.

An object of this invention is to provide a pumping system including a pressure-operated control valve arranged to delay opening of the controlled outlet until the pump has attained sufiicient rotational speed to sustain a predetermined pressure at the pump outlet, which then operates to rapidly open the controlled outlet and to regulate the pressure at the controlled outlet to maintain the pressure in a predetermined range, and which operates during shutdown of the pump to maintain the pressure at the controlled outlet in a predetermined range until the pump is slowed down to a point where it is no longer capable of maintaining this pressure and the control valve then operates to rapidly close the controlled outlet.

A more particular object of this invention is to provide a pumping system including a control valve for controlling the flow through a controlled outlet, which control valve includes a bypass for bypassing fluid from the pump to delay opening of the controlled outlet until the pump has reached a sufficient rotational speed to sustain a predetermined pressure at the controlled outlet, and which valve shuts off the bypass when it moves to a position opening the controlled outlet so that the full pump delivery is available for flow to the controlled outlet, and which valve reopens the bypass during shutdown of the pump to provide rapid closing of the controlled outlet.

Another object of this invention is to provide a pumping system including a pump, valve and a filter unit for filtering the fluids supplied to the pump and valve, which filter unit encloses the valve to reduce the overall size of the pumping apparatus and to simplify the port and passage arrangements required in the valve unit.

Still another object of this invention is to provide a pumping system including a pump, valve and filter unit in which the filter unit is removable and is so constructed as to prevent filtered particles from reaching the pump and valve when the filter is removed. I

These, together with other features, objects and advantages will become apparent from the following description when taken in connection with the accompanying drawings wherein:

FlG. l is a longitudinal sectional view through a pump, valve and filter unit embodying the present invention;

FIG. 2 is a fragmentary view shown partially in section and partially diagrammatically of the pumping system and illustrating the valve in a moved position;

FIG. 3 is an elevational view of the pumping apparatus;

FIG. d is a fragmentary view partially in section and partially diagrammatic illustrating a modified form of pumping system and filter unit; 1

FIG. 5 is a fragmentary sectional view illustrating a modified form of control valve; and

FIG. 6 is a graph illustrating the theoretical pressure-speed characteristics of the pumping system.

The pumping system is particularly adapted for use as an oil burner pump and is herein specifically illustrated and described in connection with such application. It is to be understood, however, the pumping system and apparatus disclosed herein is not necessarily limited to use with oil burner apparatus. For example, there are other applications where it is desirable to delay delivery of fluid during startup of the pump until it has reached a speed sufficient to sustain a predetermined pressure, and tocut off delivery of fluid during shutdown of the pump when the pump speed has dropped to a point where it is no longer capable of sustaining the predetermined pressure.

The pumping system in general includes a pump 10 and a control .valve ill for controlling the flow of fluid to a controlled outlet herein shown connected to an oil burner nozzle 12. The pump l0 can be of any of various different types of positive displacement pumps such as a vane or gear pump and is herein shown as a gerotor-type internal gear pump having inner and outer rotors l2 and 13 mounted for rotation about relatively eccentric axes 12a and 13a respectively and having interengaging teeth or lobes arranged to form a low-pressure pump inlet chamber designated llla at one side of the plane through the rotor axes 112a, 13a and a high-pressure pump discharge zone 10b at the other side of that plane. The pump apparatus 10 is enclosed in a pump housing advantageously formed in a plurality of sections and including a portblock 15, a ring plate rs having an opening the defining a pump chamber, and an end plate 17. The port block is conveniently formed with a circular configuration and has an end face 15a overlying one side of the pump chamber 16a and one face of the ring plate 116 and is sealed to the latter as by an O-ring lid. The end plate 17 overlies the other end of the pump chamber Mia and the other side of the ring plate 16 and is sealed to the latter as by an O-ring 19. A pump drive shaft 2i is connected to the pump and, as shown, is drivingly connected to the inner rotor 12 by drive teeth or splines 2110. The shaft extends through an opening in the end plate and a shaft seal 23 is provided to form a running seal between the shaft and end plate. The ring plate in and end plate 117 are radially positioned as by aligning pins 2d and the several parts of the pump housing including the port block 1'5, ring plate lid and end plate W are held in assembled relation as by fasteners or bolts 2%. While a single fastener is shown in the sectional views of the drawing, it is to be understood that a plurality of circumferentially spacedfasteners are employed to hold the parts in assembled relation. In the eccentric gear-type pump shown, the opening 16a in the ring plate 16 is disposed eccentric to the shaft opening 17 in the end plate 17 to rotatably support the outer rotor for rotation about its axis 130 eccentric to the axis 12a of the inner rotor. The pump apparatus can conveniently be mounted directly on the pump drive motor shown in phantom at 28 by the same fasteners 25 used to hold the sections of the pump housing in assembled relation, and the pump drive shaft 21 can conveniently comprise the extended end of the motor shaft. As shown in FIG. 1, an aligning boss 28a is conveniently provided around the shaft 21, which boss is arranged to extend into a recess 17b in the end plate 17 to radially position the motor with respect to the shaft opening 17a, and aligning pads 28b are provided on the motor housing for engagement with the end plate 17 to support the motor with its shaft parallel to the axis of the gears. Alternatively, the pump apparatus could be separately mounted and connected through a belt and pulley arrangement to a drive motor. In the embodiment shown in FIG. 3, the pump apparatus has a separate shaft 21' which is rotatably supported in a bearing (not shown) in the end plate 17 and which extends outwardly of the pump housing through a shaft seal assembly 23'.

The valve 11 is mounted on the side face 15b of the port block opposite side face 15a and the port block is made sufficiently deep to provide space in the periphery of the port block for reception of pipe or tube fittings for connection of the pumping assembly to a reservoir and nozzle, as shown in FIG. 2. The valve 11 is in the form of a self-contained valve unit and includes a valve casing having a tubular portion 31 and an enlarged mounting base 32. The valve casing is mounted on the port block as by fasteners 33 with the tubular portion substantially centered with respect to the port block and extending laterally from the side face 15b. The tubular portion 31 has a bore 31a therein for slidably receiving a valve member 34 and a counterbore 31b at the end adjacent the port block for receiving a valve seat member 35. The valve seat member is retained in the counterbore as by a retaining washer 36 and extends across the end of the bore 31a to form a high-pressure chamber 31d at the inner end of the bore. The port block has a generally crescent-shaped pump discharge groove 37 formed in the side face 15a to communicate with the pump discharge zone b at one side of the plane through the rotor axes 13a and 12a and a pump discharge passage 37b which extends from the groove 37 through the port plate and opens at the other side face b inwardly of the counterbore 31b. The valve seat member 35 has passages 38 formed therein to pass fluid from the pump discharge passage 37b into the high-pressure valve chamber 31d and the valve seat member has a generally axial bore 39 defining a controlled outlet extending therethrough and arranged to communicate with a controlled outlet passage 31 formed in the port plate and having a portion Ma extending to the outer periphery of the port plate for connection to a conduit 42 leading to the controlled apparatus such as the oil burner nozzle 12. A seal such as an O-ring 43 is provided between the valve seat member 35 and the side face 15b of the port plate to prevent leakage between the controlled outlet passage 41 and the pump discharge passage 37b and, as shown, is conveniently disposed in an annular groove in the valve seat member around the controlled outlet passage. A valve seat is provided at the inner end of the seat member 35 around the passage 39 and is advantageously in the form of an Oring 44 extending around a reduced diameter hub 45 on the seat member. The hub is formed with a slight concavity in its periphery to retain the O-ring in position and has an axial length less than the thicknem of the O-ring as shown in FIG. 2 so that the O-ring provides a resilient seat for the valve member.

The valve member 34 is in the form of a slidable plunger having an end face 3 5a defining a control valve element adapted to engage the valve seat 34 and close the controlled outlet passage 3%. The plunger is preferably made hollow as shown and a compression spring 48 has one end disposed in engagement with the plunger and the other end disposed in engagement with an adjustable abutment 49 to yieldably urge the valve member to the position shown in FIG. 1 closing the controlled outlet port. In the embodiment shown in FIGS. 1 and 2 the adjustable abutment is conveniently adjusted by means of a screw 51 threaded in a cap 52 conveniently threadedly mounted at 53 on the valve casing. As will be seen, the plunger 34 separates the high-pressure valve chamber 31d from a low-pressure valve chamber 31c at the outer end of the plunger and the latter valve chamber is vented to a lowpressure zone through openings 52a conveniently formed in the cap 52.

When the valve member is in a position as shown in FIG. 1 closing the controlled outlet port 39, the valve seat 44 around the controlled outlet port seals the area on the end face valve element 34a inwardly of the valve seat from the remaining area on the end of the plunger so that pump discharge pressure is initially applied only to the area on the end of the plunger outwardly of the valve seat 44. However, when the valve member moves to its open position as shown in FIG. 2, the entire end face of the valve element 34a is exposed to pump discharge pressure. Thus, the hydraulic force on the end of the valve plunger tending to urge it to its open position increases markedly when the valve element 34a unseats from the valve seat 44 to assure rapid opening of the valve after the predetermined pressure has been attained by the pump.

The volume of fluid delivered by the pump during startup and shutdown of the pump will not be sufficient to maintain a predetermined pressure at the controlled outlet and nozzle, at the flow rates required for the controlled outlet, until the pump has attained a predetermined speed. In order to prevent premature opening of the controlled outlet passage until the pump has attained a speed sufficient to maintain the predetermined pressure at the controlled outlet, a bypass passage is provided for bypassing fluid from the pump discharge to a low-pressure zone. This bypass passage is arranged to bypass fluid from the pump discharge at a controlled rate which rate is greater than the desired flow rate to the controlled outlet at said predetermined pressure but substantially less than full pump discharge volume, to prevent the pressure from building up in the valve chamber 31d to the predetermined pressure, until the pump has attained a speed sufficient to maintain this predetermined pressure at the desired flow rates to the controlled outlet. However, provision is also made for closing the bypass when the valve member moves to a position opening the controlled outlet, so as to thereby make the full pump discharge available to the controlled outlet. The bypass passage must have a relatively restricted size and in order to minimize clogging of the restricted bypass passage, the restricted area of the bypass passage is advantageously formed between two relatively moving surfaces on the valve member and valve casing so that movement of the valve member will tend to dislodge any foreign matter that might collect in the restricted area. In the form shown in FIGS. 1-4, the valve member has a groove 34c spaced inwardly from the inner end and which groove communicates through a passage 34d with a low-pressure zone through the hollow piston and valve chamber 31e. The valve member has an annular portion or land 34b at its inner end dimensioned to be slidably received in the bore 31a and a small recess or counterbore 31c is formed at the inner end of the valve casing around the land 34b, when the valve member is in its closed position, to define a restricted flow passage therebetween. In the drawings the actual clearance between the land 34b and the counterbore or recess 31c has been exaggerated for purpose of illustration and in actual practice the clearance between the land and the annular wall is very small on the order of a few thousandths of an inch.

Thus, when the valve member is in a position closing the controlled port 39, fluid from the pump discharge is bypassed through the restriction around the land 34b and through groove 34c and passage 34d. As the valve member moves to its open position, the land 34b moves into the bore portion 31a as shown in FIG. 2 and substantially shuts off the flow of fluid through the bypass including passage Eldd. The valve member Ed is also arranged to control flow of fluid to a relief passage when the controlled outlet is open, to regulate the pressure on the fluid delivered to the controlled outlet. In the embodiment shown in FllGS. l and 2, a relief port dllf is formed in the valve casing and the valve member has a groove Me that communicates through a passage 34f with the high-pressure chamber Zillc. The groove 3% is positioned on the valve member and in relation to the relief valve port 3llf such that the relief port is closed when the valve member is in the position shown in FIG. ll closing the controlled outlet port 39, and the groove Me does not beg'n to register with the relief port Ell f until the valve member has moved away from the seat dd, to a position blocking flow through the bypass including passage Md. Specifically, the maximum spacing of the relatively outer edges of grooves Me and dds on the valve member is made equal to or preferably slightly less than the minimum spacing between the relatively inner edges of the recess Elli c and the relief port 31f so that the bypass is closed at about the time the relief passages is opened, and vice versa. Thus, the valve member is movable from a first position as shown in FlG. l in which it closes the controlled port 39 and the relief port 31f and opens the bypass passage to bypass a restricted flow of fluid from the pump discharge to a lowpressure zone. When the pressure builds up in the valve chamber 3110 to a predetermined value, the valve member begins to move away from the seat M and at that time the entire end of the valve member is exposed to the high-pressure end chamber title so that the valve member moves rapidly through an intermediate position in which it shuts off bypass of fluid through passage 34ld to a third position shown in FIG. 2 in which it variably opens the relief port 31f to regulate the pressure supplied to the controlled outlet.

it is important to prevent entrance of dirt and other foreign material into the valve and pump and a filter is commonly provided to filter the fluid. The filter unit disclosed herein is arranged to enclose the valve unit so as to provide a more compact overall package and to simplify the valve passages required for circulating and bypassing fluid, and the filter unit is so constructed as to prevent the filtered particles from reaching the pump or valve as the filter is removed from around the valve. As best shown in FlG. l, the port block has a supply inlet passage d formed therein, which inlet passage has one end thereof opening at the outer periphery of the valve block and To adapted for connection as by thread 55a to a fluid supply line so leading to a supply reservoir 5'7 diagrammatically shown in FlGS. 2 and d. The other end 55a to a fluid supply line so leading to a supply reservoir 5'7 diagrammatically shown in FlGS. 2 and 4 The other end 55b of the inlet passage 55 opens at the side face lfib of the port block at a location outwardly of the valve unit. The filter unit includes a generally cup-shaped filter case 5% which is detachably mounted on the pump housing to enclose the valve unit, and a filter element L3 9 mounted in the filter case for removal as a unit therewith. The filter element 59 is of generally tubular form and dimensioned larger than the valve unit to extend around the ladder and form an inner filter compartment inside the filter unit. The filter unit can be of any convenient construction and may, for example, be formed of fiber, ceramic or even a closely woven mesh. The particular filter element shown in section in the drawings is a commercially available filter element formed by a helically wound rosin impregnated cellulose ribbon which provides a somewhat thick walled filter element, it being understood that other forms such as a longitudinally pleated fiber filter element could be used. The filter case 5% includes a peripheral wall portion hilt: which is spaced outwardly from the filter element W, an outer end wall portion dhb that engages the outer end of the tubular filter element, and a generally annular inner wall dd that eirmnds between the peripheral wall dds and the inner end of the filter element 59. The inner wall M has an annular portion dds of generally U-shaped cross section disposed between the peripheral wall We of the filter case and the inner end of the filter element 59 to laterally space the same and the U-shaped portion 64a opens in a direction toward the side face 15b of the port block to define an annular fluid distribution channel 64b aroundthe filter case for communication with the supply inlet opening 55b. Openings as are formed in the intermediate portion to pass fluid from the channel Mb into the inlet filter chambers 63a. The annular wall portion 64 also has inner and outer flanges 64d and 64e respectively overlying the inner side of the filter 59 and the outer side of the case wall 58a adjacent one end thereof to hold the same in assembled relation. The filter unit is detachably mounted on the pump housing and the inner flange Md is conveniently internally threaded to threadedly engage the extemally threaded portion 32a on the base of the valve unit. A gasket 65 is disposed between the end face 15b of the port block and the inner end wall 64 of .the valve case to form radially inner and outer seals therebetween at opposite sides of the channel 64b. The gasket, of course, has openings 65a to allow fluid to pass from the inlet passage 55b to the channel Mb. In the form shown in FIGS. 1 and 2, the filter case has an end wall 5% that overlies the end of the valve member and encloses the same. Fluid from the supply unit thus passes into the outer filter chamber 63a and through the filter into the inner filter chamber 63b. Filtered fluid from the chamber 63b is passed to the pump inlet zone 10a through passages 66 and 67 in the valve casing base 32 and port plate 15 respectively. The filtered fluid is delivered by the pump to the valve chamber 31d. A gauge passage 69 extending from the pump discharge passage 37b to a gauge port 711 is conveniently provided and adapted to receive a pressure gauge (not shown) to enable measurement of the pressure delivered by the pump. The gauge passage can also be used to bleed off air in the pump system, when initially installing the pump by merely loosening the gauge connected to the fittings 71. Alternatively, a plug not shown can be threaded into the gauge port 71 to close the same.

The pumping system illustrated in FIG. 4 is generally similar to that illustrated and described in connection with FIGS. 1 and 2 and like numerals are used to designate the same parts while like numerals followed by the postscript are used to designate modified parts. In this form, the valve casing and port block have been modified slightly to return fluid from the bypass and relief passages back to the reservoir instead of into the inner filter compartment as in FIG. 11, and the filter case has been modified slightly so as to allow adjustment of the control valve operating pressure from extemally of the filter unit without removing the same. In this embodiment, a plug 52" is mounted on the outer end of the valve casing 31 to close the outer end of the valve casing and, as shown, is sealed to the casing by a gasket 52b". The adjusting screw Sll is threadedly mounted in the cap 52" and a cover 60" is detachably mounted on the cap and sealed thereto by gasket 6%". The valve chamber 31c and the relief valve port 31f are vented through passages 52a" and 311" in the valve casing and through a passage 50" in the port block to a return line She" leading to the reservoir. Thus, in this embodiment, fluid which flows through the bypass passage Md into the valve chamber die and fluidwhich flows through the relief passages 3H1" is passed back to the reservoir instead of into the inner filter chamber 63b, as in the preceding embodiment. Fluid from the inner filter chamber is, however, still fed through passages as and 67 to the intake of the pump ltl.

The filter case 5% has a modified outer end wall portion Ede" which is sealed to the outer periphery of the valve casing as by an O-ring 5311" to enclose the inner filter compartment 631; while yet allowing the end of the valve casing to be uncovered by removal of the cover 6d" for adjustment of the screw 5B. As is apparent, the pumping system shown in FIG. All in which the bypass and relief fluid is returned to the reservoir, can be converted to a single pipe system by merely plugging the passage 50" and by removing the plug Ell" at the inner end of the passage 31] in the valve casing.

FIG. illustrates a control valve having a slightly modified form of bypass passage. Sln this embodiment, the valve member 34 also has a peripheral groove 34 c and a passage 34d communicating the groove with a low-pressure zone inside the valve member. However, instead of forming the restricted portion of the bypass passage by an annular recess as shown at 310 in FIGS. 1 and 2, the restricted passage is fomred by one or more longitudinally extending grooves 31c" in the valve casing, which grooves are arranged to pass a restricted flow of fluid around the land 34b of the valve member when the valve is in its closed position, and which groove terminates intermediate the ends of the valve casing at a position such that the land 34b closes off flow through the grooves 31c" when the valve member moves to its open position.

'Ihe graph in FIG. 6 has been prepared to show typical curves illustrating the change in pump capacity and pressures with pump speed during startup and stopping of the pump. The curves shown in FIG. 6 are theoretical curves based upon the following assumptions;

a. Desired flow through the nozzle 2 gallons per hour at I00 p.s.r.

b. Pump capacity gallons per hour at 1800 rpm.

c. Bypass flow 5 gallons per hour at I00 p.s.i.

d. Leakage through valve l gallon per hour at 100 p.s.i.

e. The valve closing spring is adjusted to urge the valve to a closed position with a force such that the valve member will not move away from its seat 44 until the fluid pressure acting on the end area of the valve member outside the valve seat 44 reaches 100 p.s.i.

When the pump motor is started, the pressure in the valve chamber 310 builds up along the line 0-A in FIG. 6 until the pump reaches a speed of about I060 rpm. at which it delivers a flow of 6 gallons per hour equivalent to the combined flow through the bypass passage and the valve leakage, at I00 psi. The valve member then moves away from the seat 44 and exposes the remaining area on the end of the valve member to the pressure in the valve chamber 31c to thereby effect a rapid opening of the valve. When the valve opens the controlled outlet port, flow to one nozzle commences at about 2 gallons per hour. However, as the valve moves to its open position it closes the bypass passage to substantially cut off the 5 gallons per hour bypass flow, thereby assuring an adequate quantity of fluid for the nozzle. As the valve moves further toward its open position, it uncovers the relief port 31] and variably controls flow through the relief port to maintain the pressure at the nozzle in a predetermined range. The force exerted by the spring 48 on the valve member progressively increases as the valve member moves to its open position shown in FIG. 2. In order to compensate for the increased force required to move the valve member to its position regulating flow through the relief port, the diameter of the valve seat 44 is selected in relation to the cross-sectional area of the valve member such that the increase in hydraulic thrust that occurs when the valve member moves away from the seat 44 (due to the exposure of the area on the end of the valve member inwardly of the seat 44 to the hydraulic pressure) is sufficient to overcome the increased force exerted by the spring 48 as the valve member moves to its relief position. With this arrangement, the pressure in the relief valve chamber 31c will remain substantially constant as the pump speed increases from its valve opening speed of 1060 rpm. to its full speed of I800 r.p.m., as shown by the line A-B in FIG. 6. While the pump is operating at full speed, the valve of course operates to regulate flow the relief passage to maintain the predetermined minimum pressure. When the pump motor is thereafter deenergized, the pump slows down with a consequent decrease in flow and the valve member moves to progressively throttle flow through the relief passage as indicated by the line B-C in FIG. 6 so as to maintain the predetermined pressure at the nozzle until the pump speed falls to a point designated C such that the pump output is only sufficient to supply the nozzle flow rate of 2 gallons per hour plus the leakage flow rate of 1 gallon per hour. At that time, there is no more flow through the relief valve and the valve can no longer maintain the pressure. However, the valve member then opens the bypass through passage 34d at which time pressure in chamber 31d drops rapidly so that the valve member can rapidly move to a closed position shutting off flow to the nozzle. Flow will continue through the bypass passage while the pump coasts to a stop so as to prevent spurious reopening of the controlled outlet port.

From the foregoing it is thought that the construction and operation of the pumping system will be readily understood. The valve of the pumping system delays opening of the controlled outlet port until the pump attains a speed sufficient to sustain a predetermined minimum pressure at the flow rates required for the controlled outlet, and the valve member operates to maintain this predetermined pressure during operation of the valve. When the pump motor is deenergized, the valve operates to shut off flow to the controlled outlet as soon as the pump speed drops to a level where it is insufficient to maintain the predetermined pressure at the desired flow rates, and thereafter the valve bypasses the pump output. The filter is mounted on the pump so as to surround the valve unit to thereby provide a compact overall pumping apparatus while simplifying the porting and passage arrangement required. Moreover, the valve itself can be removed as a unit and is so constructed that it can be pretested for the desired operating characteristics before assembly on the pump. The filter case defines a confined inlet filter compartment around the filter element so that, when the filter unit is removed, any filtered material is contained or retained in the inlet filter compartment and cannot pass into the valve or pump. In the embodiment of FIGS. 1 and 2 it is necessary to remove the filter unit in order to adjust the valve while in the embodiment of FIG. 4, the filter case is arranged so that the valve can be adjusted while the filter unit is in position.

lclaim:

1. In a pumping system for intermittently pumping fluid from a low-pressure zone and for delivering fluid to a controlled outlet at a pressure in a selected elevated pressure range, said pumping system including pump means having a low-pressure pump inlet adapted to receive fluid from said low-pressure zone and a high-pressure pump outlet, motor means for intermittently driving the pump means, and valve means for controlling the flow of fluid from the high-pressure pump outlet, said valve means including valve casing means defining a chamber and a pressure responsive valve plunger slidable in said chamber, said valve casing means and valve plunger having control passage means and cooperating control valve elements operable in a first position of the plunger to block flow from the high-pressure pump outlet to the controlled outlet and operable when the plunger is moved away from said first position to pass fluid from the pump outlet to the controlled outlet, spring means yieldably urging said valve plunger to said first position with a force to prevent movement of said plunger away from said first position until the pressure in said high-pressure pump outlet rises to a preselected pressure, said valve casing means and said plunger having bypass passage means and a cooperating bypass valve elements operable when said plunger is in said first position to pass a restricted flow of fluid from said high-pressure pump outlet to said low-pressure zone and operable to at least substantially shut-off flow through said bypass passage means when the valve plunger moves away from said first position to an intermediate position, said valve casing means and plunger having relief passage means and cooperating relief valve elements controlling flow from said high-pressure pump outlet to said low-pressure zone and operable when the valve plunger is in said first position and in said intermediate position to substantially close said relief passage means and operable as the valve plunger moves from the intermediate position to a third position to variably open the relief passage means and regulate the maximum pressure supplied to the controlled port.

2. in a pumping system for intermittently pumping fluid from a low-pressure zone and for delivering fluid to a controlled outlet at a pressure in a selected pressure range, said pumping system including pump means having a lowpressure pump inlet adapted to receive fluid from said lowpressure zone and a high-pressure pump outlet, motor means for intermittently driving the pump means, and valve means for controlling the flow of fluid from the high-pressure pump outlet, said valve means including valve casing means defining a valve chamber having a tubular sidewall and a first end wall at one end of the chamber, a pressure responsive valve plunger slidable in said chamber and separating the latter into a high-pressure compartment at one end of the plunger and a low-pressure compartment at the other end of the plunger, a first passage means communicating the high-pressure compartment with the pump outlet and a second passage means communicating the low-pressure compartment to said low-pressure zone, said casing means having a control port in said first end wall and a control valve element on said one end of said plunger cooperable with said control port to block flow from the high-pressure compartment to said control port when the plunger is in a first position, said control port sealing one area on the end face of said plunger from the remaining area on the end face of said plunger when the latter is in said first position, spring means yieldably urging said plunger to said first position with a force to prevent movement of the plunger away from said first position until the pump discharge pressure acting on said remaining area at said one end of the plunger rises to a preselected pressure, said valve casing means and said plunger having bypass passage means and cooperating bypass valve elements operable when said plunger is in said first position to pass a restricted flow of fluid from said highpressure compartment to said low-pressure zone and operable to at least substantially shut off flow through said bypass passage means when the valve plunger moves away from said first position to an intermediate position, said valve casing means and plunger having relief valve passage means and cooperating relief valve elements controlling flow from said high-pressure compartment to said low-pressure zone and operable when said valve plunger is in said first position and said intermediate position to substantially close said relief passage means and operable when said valve plunger moves from said intermediate position to a third position to variably open said relief passage means and regulate the maximum pressure supplied to the control port.

it. A pumping system according to claim 2 wherein said bypass passage means includes means defining a restricted flow passage at the interface between the sidewall of the valve chamber and the periphery of the plunger operative to pass a restricted flow of fluid therethrough from the high-pressure compartment to said low-pressure zone when the plunger is in said first position.

i. A pumping system according to claim 2 wherein said cooperating bypass valve elements and said cooperating relief valve elements comprise slidably interfitting portions on the periphery of the plunger and said sidewall of the chamber.

a. A pumping system according to claim 2 wherein said bypass passage means includes a bypass recess in the sidewall of said chamber communicating with said high-pressure compartment and terminating intermediate the ends of the sidewall and a first passage in said plunger communicating at one end with the low-pressure zone and opening at the outer periphery of the plunger intermediate its ends, said bypass valve element comprising an annular land on said plunger between said first passage in said plunger and said one end thereof operative when the plunger is in said first position to allow fluid flow from said recess in the sidewall of the chamber through said first passage in the plunger and operative when the plunger is in said intermediate and third positions to substantially bloclt flow from said recess to said first passage in the plunger.

n. A pumping system according to claim h wherein said bypass recess comprises an annular counterbore in said sidewall of the chamber having a diameter sufficiently larger than said on the plunger to define a restricted bypass passage therebetween when the plunger is in said first position.

7. A pumping system according to claim 5 when said bypass recess comprises at least one groove extending longitudinally in said sidewall of the chamber and defining a restricted bypass passage with said land on the plunger when the latter is in said first position.

b. A pumping system according to claim 5 wherein said relief passage means includes a relief port in said sidewall of said chamber spaced from said bypass recess and communicating with said low-pressure zone, said relief passage means also including a second passage in said plunger communicating with said high-pressure compartment and opening at the outer periphery of the plunger at a point intemrecliate said first passage and the other .end of the plunger at a location to communicate with said relief port only when the plunger moves away from said intermediate position toward said third position thereof.

9. A pump apparatus comprising a pump housing and pump means in the housing defining pump inlet and discharge zones, a valve unit mounted on one side of the pump housing, a filter unit including a filter case and an annular filter element mounted in said filter case for removal as a unit therewith, said case having a peripheral sidewall spaced outwardly from the filter element and first and second end wall means sealingly engaging the filter element adjacent opposite ends thereof to form an outer filter compartment between the filter element and the sidewall of the filter case, means detachably mounting the filter unit on the pump'housing with said first end wall means of the filter case sealingly engaging said one side of the pump housing and with the filter unit extending around the valve unit to define an inner filter compartment internally of the filter element and around the valve unit, said first end wall means of the filter case having inlet openings therein communicating with said outer filter compartment, said pump housing having a supply passage adapted for connection to a supply source and opening at said one side at a location between the filter element and the sidewall of the filter case for communication with said inlet openings in the first end wall of the case, said pump housing also having pump inlet passage means communicating said pump inlet zone with said inner filter compartment and pump discharge passage means communicating said pump discharge zone with said valve unit.

it). A pumping system according to claim 9 wherein said valve unit is detachably mounted on said pump housing and is removable as a unit therefrom after removal of said filter unit.

ll. A pumping system according to claim 9 wherein said valve unit has an annular base and threads on the periphery of the base, said filter case having internal threads adjacent said one end wall engageable with the threads on the base of the valve unit to detachably mount the filter unit on the pump housing.

12. A pumping system according to claim 9 wherein said first end wall means on the filter case has an annular portion of U-shaped cross section disposed between the sidewall of the filter case and the filter element and opening in a direction toward said one end of the pump housing to define an annular fluid distribution channel therewith.

13. A pumping system according to claim 12 wherein said first end wall has inner and outer flanges respectively overlying end portions of the inner side of the filter element and the outer side of the filter case.

M. A pumping system according to claim 12 in which said inner flange has threads on the inner side thereof and said valve unit has an externally threaded base portion engaging said threaded inner flange to detachably mount the filter unit on the pump housing.

15. A pump apparatus comprising a port block having first and second relatively parallel side faces, pump means including a pump casing and pump elements in the casing mounted at said first side face of the port block and defining pump inlet and discharge zones therewith, a valve unit including a valve casing having a base detachably mounted on said second side face of the port block, said valve casing defining a cylindrical valve chamber extending laterally from said second side face, a filter unit including a filter case and an annular filter element mounted in said filter case for removal as a unit therewith, said case having a peripheral sidewall spaced outwardly from the filter element and first and second end wall means sealingly engaging the filter element adjacent opposite ends thereof to form an outer filter compartment between the filter element and the sidewall of the filter case,

means detachably mounting the filter unit on the port block with said first end wall means of the filter case sealingly engaging said second side face of the port block and with the filter unit extending around the valve unit to define an inner filter compartment internally of the filter element and around the valve unit, said first end wall means having inlet openings therein communicating with said inlet filter chamber, said port plate having (a) a pump inlet passage communicating said pump inlet zone with said inner filter compartment; (b) a pump discharge passage communicating said pump discharge zone with said valve chamber; (c) a supply inlet passage adapted for connection to an external supply and having on end opening at said second side face of the port block in communication with the inlet openings in the filter case, and (d) a controlled outlet passage communicating with said valve chamber and adapted for connection to a controlled fluid delivery line, said valve casing having valve means therein for controlling flow from said pump discharge passage to said controlled outlet passage.

16. In a pumping system for intermittently pumping fluid from a low-pressure zone and for delivering fluid to a controlled outlet at a pressure in a selected pressure range, said pumping system including pump means having a lowpressure pump inlet adapted to receive fluid from said lowpressure zone and a high-pressure pump outlet, motor means for intermittently driving the pump means, and valve means for controlling the flow of fluid from the high-pressure pump outlet, said valve means including valve casing means defining a valve chamber having a tubular sidewall and first end wall means at one end of said chamber, a pressure responsive valve plunger slidable in said chamber and separating the latter into a high-pressure compartment between said first end wall means and one end of the plunger and a low-pressure compartment at the other end of the plunger, said plunger being movable in said chamber from a first position adjacent said first end wall means through an intermediate position to a third position spaced from said first end wall means, a first passage means communicating the high-pressure compartment with the pump outlet and a second passage means communicating the low-pressure compartment to said low pressure zone, said casing means having a control port in said first end wall means and a control valve element on said one end of said plunger cooperable with said control port to block flow from the high-pressure compartment to said control port when the plunger is in said first position, said control port sealing one area on the end face of said plunger from the remaining area on the end face of said plunger when the latter is in said first position, spring means yieldably urging said plunger to said first position with a force to prevent movement of the plunger away from said first position until the pump discharge pressure acting on said remaining area at said one end of the plunger rises to a preselected pressure, said valve casing means and said plunger having bypass passage means and cooperating bypass valve elements operable when said plunger is in said first position to pass a restricted flow of fluid from said high-pressure compartment to said low-pressure zone and operable to throttle flow through said bypass passage means when the valve plunger moves away from said first position to said intermediate position and said third position, said valve casing means and plunger having relief valve passage means and cooperating relief valve elements controlling flow from said high-pressure compartment to said low-pressure zone and operable when said valve plun er is in said first position and said intermediate post ion to substantially close said relief passage means and operable when said valve plunger moves from said intermediate position to a third position to variably open said relief passage means and regulate the maximum pressure supplied to the control port.

$9713 3 UNITED STATES PATENT OFFICE D GERTIFECATE OF CORRECTEON Patent No. 3 575 296 Dated April 20 1971 Inventor(s) Kenneth E. Peterson It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 10 line 2 after "said" should be inserted land Column 11, line 22 "on" should be one Signed and sealed this 7th day of September 1971 (SEAL) Attest:

EDWARD M.FLETCHER,J'R. ROBERT GOTTSCIIALK Attesting Officer Acting Commissioner of Paten 

1. In a pumping system for intermittently pumping fluid from a low-pressure zone and for delivering fluid to a controlled outlet at a pressure in a selected elevated pressure range, said pumping system including pump means having a low-pressure pump inlet adapted to receive fluid from said low-pressure zone and a highpressure pump outlet, motor means for intermittently driving the pump means, and valve means for controlling the flow of fluid from the high-pressure pump outlet, said valve means including valve casing means defining a chamber and a pressure responsive valve plunger slidable in said chamber, said valve casing means and valve plunger having control passage means and cooperating control valve elements operable in a first position of the plunger to block flow from the high-pressure pump outlet to the controlled outlet and operable when the plunger is moved away from said first position to pass fluid from the pump outlet to the controlled outlet, spring means yieldably urging said valve plunger to said first position with a force to prevent movement of said plunger away from said first position until the pressure in said high-pressure pump outlet rises to a preselected pressure, said valve casing means and said plunger having bypass passage means and a cooperating bypass valve elements operable when said plunger is in said first position to pass a restricted flow of fluid from said high-pressure pump outlet to said lowpressure zone and operable to at least substantially shut-off flow through said bypass passage means when the valve plunger moves away from said first position to aN intermediate position, said valve casing means and plunger having relief passage means and cooperating relief valve elements controlling flow from said high-pressure pump outlet to said low-pressure zone and operable when the valve plunger is in said first position and in said intermediate position to substantially close said relief passage means and operable as the valve plunger moves from the intermediate position to a third position to variably open the relief passage means and regulate the maximum pressure supplied to the controlled port.
 2. In a pumping system for intermittently pumping fluid from a low-pressure zone and for delivering fluid to a controlled outlet at a pressure in a selected pressure range, said pumping system including pump means having a low-pressure pump inlet adapted to receive fluid from said low-pressure zone and a high-pressure pump outlet, motor means for intermittently driving the pump means, and valve means for controlling the flow of fluid from the high-pressure pump outlet, said valve means including valve casing means defining a valve chamber having a tubular sidewall and a first end wall at one end of the chamber, a pressure responsive valve plunger slidable in said chamber and separating the latter into a high-pressure compartment at one end of the plunger and a low-pressure compartment at the other end of the plunger, a first passage means communicating the high-pressure compartment with the pump outlet and a second passage means communicating the low-pressure compartment to said low-pressure zone, said casing means having a control port in said first end wall and a control valve element on said one end of said plunger cooperable with said control port to block flow from the high-pressure compartment to said control port when the plunger is in a first position, said control port sealing one area on the end face of said plunger from the remaining area on the end face of said plunger when the latter is in said first position, spring means yieldably urging said plunger to said first position with a force to prevent movement of the plunger away from said first position until the pump discharge pressure acting on said remaining area at said one end of the plunger rises to a preselected pressure, said valve casing means and said plunger having bypass passage means and cooperating bypass valve elements operable when said plunger is in said first position to pass a restricted flow of fluid from said high-pressure compartment to said low-pressure zone and operable to at least substantially shut off flow through said bypass passage means when the valve plunger moves away from said first position to an intermediate position, said valve casing means and plunger having relief valve passage means and cooperating relief valve elements controlling flow from said high-pressure compartment to said low-pressure zone and operable when said valve plunger is in said first position and said intermediate position to substantially close said relief passage means and operable when said valve plunger moves from said intermediate position to a third position to variably open said relief passage means and regulate the maximum pressure supplied to the control port.
 3. A pumping system according to claim 2 wherein said bypass passage means includes means defining a restricted flow passage at the interface between the sidewall of the valve chamber and the periphery of the plunger operative to pass a restricted flow of fluid therethrough from the high-pressure compartment to said low-pressure zone when the plunger is in said first position.
 4. A pumping system according to claim 2 wherein said cooperating bypass valve elements and said cooperating relief valve elements comprise slidably interfitting portions on the periphery of the plunger and said sidewall of the chamber.
 5. A pumping system according to claim 2 wherein said bypass passage means includes a bypass recess in the sidewall of said chamber communicating with said high-pressure compartmeNt and terminating intermediate the ends of the sidewall and a first passage in said plunger communicating at one end with the low-pressure zone and opening at the outer periphery of the plunger intermediate its ends, said bypass valve element comprising an annular land on said plunger between said first passage in said plunger and said one end thereof operative when the plunger is in said first position to allow fluid flow from said recess in the sidewall of the chamber through said first passage in the plunger and operative when the plunger is in said intermediate and third positions to substantially block flow from said recess to said first passage in the plunger.
 6. A pumping system according to claim 5 wherein said bypass recess comprises an annular counterbore in said sidewall of the chamber having a diameter sufficiently larger than said on the plunger to define a restricted bypass passage therebetween when the plunger is in said first position.
 7. A pumping system according to claim 5 when said bypass recess comprises at least one groove extending longitudinally in said sidewall of the chamber and defining a restricted bypass passage with said land on the plunger when the latter is in said first position.
 8. A pumping system according to claim 5 wherein said relief passage means includes a relief port in said sidewall of said chamber spaced from said bypass recess and communicating with said low-pressure zone, said relief passage means also including a second passage in said plunger communicating with said high-pressure compartment and opening at the outer periphery of the plunger at a point intermediate said first passage and the other end of the plunger at a location to communicate with said relief port only when the plunger moves away from said intermediate position toward said third position thereof.
 9. A pump apparatus comprising a pump housing and pump means in the housing defining pump inlet and discharge zones, a valve unit mounted on one side of the pump housing, a filter unit including a filter case and an annular filter element mounted in said filter case for removal as a unit therewith, said case having a peripheral sidewall spaced outwardly from the filter element and first and second end wall means sealingly engaging the filter element adjacent opposite ends thereof to form an outer filter compartment between the filter element and the sidewall of the filter case, means detachably mounting the filter unit on the pump housing with said first end wall means of the filter case sealingly engaging said one side of the pump housing and with the filter unit extending around the valve unit to define an inner filter compartment internally of the filter element and around the valve unit, said first end wall means of the filter case having inlet openings therein communicating with said outer filter compartment, said pump housing having a supply passage adapted for connection to a supply source and opening at said one side at a location between the filter element and the sidewall of the filter case for communication with said inlet openings in the first end wall of the case, said pump housing also having pump inlet passage means communicating said pump inlet zone with said inner filter compartment and pump discharge passage means communicating said pump discharge zone with said valve unit.
 10. A pumping system according to claim 9 wherein said valve unit is detachably mounted on said pump housing and is removable as a unit therefrom after removal of said filter unit.
 11. A pumping system according to claim 9 wherein said valve unit has an annular base and threads on the periphery of the base, said filter case having internal threads adjacent said one end wall engageable with the threads on the base of the valve unit to detachably mount the filter unit on the pump housing.
 12. A pumping system according to claim 9 wherein said first end wall means on the filter case has an annular portion of U-shaped cross section disposed between the sIdewall of the filter case and the filter element and opening in a direction toward said one end of the pump housing to define an annular fluid distribution channel therewith.
 13. A pumping system according to claim 12 wherein said first end wall has inner and outer flanges respectively overlying end portions of the inner side of the filter element and the outer side of the filter case.
 14. A pumping system according to claim 12 in which said inner flange has threads on the inner side thereof and said valve unit has an externally threaded base portion engaging said threaded inner flange to detachably mount the filter unit on the pump housing.
 15. A pump apparatus comprising a port block having first and second relatively parallel side faces, pump means including a pump casing and pump elements in the casing mounted at said first side face of the port block and defining pump inlet and discharge zones therewith, a valve unit including a valve casing having a base detachably mounted on said second side face of the port block, said valve casing defining a cylindrical valve chamber extending laterally from said second side face, a filter unit including a filter case and an annular filter element mounted in said filter case for removal as a unit therewith, said case having a peripheral sidewall spaced outwardly from the filter element and first and second end wall means sealingly engaging the filter element adjacent opposite ends thereof to form an outer filter compartment between the filter element and the sidewall of the filter case, means detachably mounting the filter unit on the port block with said first end wall means of the filter case sealingly engaging said second side face of the port block and with the filter unit extending around the valve unit to define an inner filter compartment internally of the filter element and around the valve unit, said first end wall means having inlet openings therein communicating with said inlet filter chamber, said port plate having (a) a pump inlet passage communicating said pump inlet zone with said inner filter compartment; (b) a pump discharge passage communicating said pump discharge zone with said valve chamber; (c) a supply inlet passage adapted for connection to an external supply and having on end opening at said second side face of the port block in communication with the inlet openings in the filter case, and (d) a controlled outlet passage communicating with said valve chamber and adapted for connection to a controlled fluid delivery line, said valve casing having valve means therein for controlling flow from said pump discharge passage to said controlled outlet passage.
 16. In a pumping system for intermittently pumping fluid from a low-pressure zone and for delivering fluid to a controlled outlet at a pressure in a selected pressure range, said pumping system including pump means having a low-pressure pump inlet adapted to receive fluid from said low-pressure zone and a high-pressure pump outlet, motor means for intermittently driving the pump means, and valve means for controlling the flow of fluid from the high-pressure pump outlet, said valve means including valve casing means defining a valve chamber having a tubular sidewall and first end wall means at one end of said chamber, a pressure responsive valve plunger slidable in said chamber and separating the latter into a high-pressure compartment between said first end wall means and one end of the plunger and a low-pressure compartment at the other end of the plunger, said plunger being movable in said chamber from a first position adjacent said first end wall means through an intermediate position to a third position spaced from said first end wall means, a first passage means communicating the high-pressure compartment with the pump outlet and a second passage means communicating the low-pressure compartment to said low-pressure zone, said casing means having a control port in said first end wall means and a control valve element on said one end of said plUnger cooperable with said control port to block flow from the high-pressure compartment to said control port when the plunger is in said first position, said control port sealing one area on the end face of said plunger from the remaining area on the end face of said plunger when the latter is in said first position, spring means yieldably urging said plunger to said first position with a force to prevent movement of the plunger away from said first position until the pump discharge pressure acting on said remaining area at said one end of the plunger rises to a preselected pressure, said valve casing means and said plunger having bypass passage means and cooperating bypass valve elements operable when said plunger is in said first position to pass a restricted flow of fluid from said high-pressure compartment to said low-pressure zone and operable to throttle flow through said bypass passage means when the valve plunger moves away from said first position to said intermediate position and said third position, said valve casing means and plunger having relief valve passage means and cooperating relief valve elements controlling flow from said high-pressure compartment to said low-pressure zone and operable when said valve plunger is in said first position and said intermediate position to substantially close said relief passage means and operable when said valve plunger moves from said intermediate position to a third position to variably open said relief passage means and regulate the maximum pressure supplied to the control port. 